A significant problem in display systems using cathode ray tubes, especially in color television systems, involve the provision of a uniform layer of phosphors on the inner face of the display screen. In particular, problems of uneven coverage at edges and comers of the display screen have traditionally occurred.
While various attempts at achieving uniform displays screens have been tried in the past, see European Patent Application No. 0 647 959, for example, these prior attempts have failed to achieve the results necessary in the field. The latter reference is directed at xerox-type devices, using a panel instead of paper and phosphors instead of ink. This type of device also uses a Tribo-charging system which is insufficient because significant drift occurs. Also, such a device requires a separate layer of conductive material and exposure through a mask before applying the phosphor.